1. Technical Field
The present invention relates in general to an automated step device and, in particular, to an improved system, method, and apparatus for an electric slide step for a recreational vehicle.
2. Description of the Related Art
Recreational vehicles typically have exterior doors that are elevated well above the surface supporting the vehicle. Access to recreational vehicles can be difficult and even unsafe, especially for older persons who often use such vehicles. A series of permanent steps attached beneath the doorway to permit easy access are not practical, since the steps would decrease the effective clearance of the vehicles and extend the width or length of the vehicle as well. Such steps are typically mounted to the RV frame for stability and are best provided at a point somewhat outside the vertical plane formed by the side of the RV, so that a person exiting the RV may step through the door while facing forward.
Any step fixed at a location outside the vertical plane formed by the side of the RV poses a hazard when the RV is in motion. For that reason, it is helpful to have a step that may be extended when the vehicle is stationary, and retracted when the vehicle is in motion. Various steps capable of this function have been proposed. For example, U.S. Pat. No. 3,955,827, discloses a stowable step for vehicles, the stowing action of which is accomplished by a system of slotted supports and links which work to fold the step under the vehicle. That design is complicated, using many moving parts to accomplish this stowing function. Other typical systems are likewise complicated. They may require specialized tools to assemble or attach them to the frame. They may be sufficiently complicated that it is practical only to assemble the entire system at the point of manufacture, which leads to increased costs for shipping the unit or for attaching it to the RV frame. Additionally, they may be susceptible to breakdown or malfunction because of the failure of one of many parts.
U.S. Pat. No. 3,876,230 discloses foldable camper steps that pivot on one another until they reach a fully retracted position. Each of the steps is formed from an L-shaped member. However, several problems exist with the application of this step assembly to a recreational vehicle. The door of a recreational vehicle is typically on the side. As such, very little or no increase in width beyond the door can be allowed by the steps when they are not in use. Even when fully retracted, the steps extend at least the width of one step beyond the door. Another problem with the Phillips steps is in the shallowness of the depth of the step treads. A user may not be able to fit his or her entire foot onto the tread.
U.S. Pat. No. 3,408,959 discloses a folding staircase which functions as a raised step for use with high-level platforms, as well as a pair of steps for lower-level platforms. This step assembly includes an upper tread and a lower tread linked together and actuated by the flotation of a pivot arm and an associated link through a chain drive, powered by a motor. When these steps are in a fully retracted position, an outside wall or member forms a part of the exterior of the vehicle.
U.S. Pat. No. 4,106,790 discloses a retractable vehicle step that swings into a retracted position. The step is mounted on the side of a recreational vehicle and stowed beneath the door under the side of the vehicle when not in use. However, since only one steps is disclosed, safe and convenient access may be somewhat less than desirable. If the frame height of the step is kept within a reasonable range for ground clearance purposes, the distance from the step to the ground may be excessive. If the step did project lower, the distance from the door threshold to the step may be excessive.
U.S. Pat. No. 4,424,751 discloses a step assembly for rail cars, which is raised and lowered by two parallel guide brackets. This step assembly contains an upper and a lower tread. When the lower tread is in its retracted position the bottom surface of the step conforms to the exterior of the rail car. However, the step assembly does reduce the amount of usable floor space within the rail car due to the operation and structure of the step assembly.
U.S. Pat. No. 3,807,757 also discloses a step assembly for campers, trucks, and other recreational vehicles. The step assembly has upper, center, and lower treads. When the step assembly is in its fully retracted position, the bottom of the lower tread faces outwardly. However, even in its fully retracted position the step assembly does add additional width to the side of the recreational vehicle to which it is attached. As is typical in such step assemblies, the carpenter step assembly is rather unsightly when in a fully folded position.
Another problem associated with the retracting and extending function of the step is the need to keep the step in the desired position while maintaining ease of movement between the retracted and extended positions. When the RV is in motion, bumps or sharp turns in the roadway might induce the step to move unexpectedly from the retracted position, creating a hazard. Alternatively, when the RV is stationary, a person stepping onto the step might be injured if the stepping force caused the step to move unexpectedly toward the retracted position.
It is therefore desirable to have a step that includes relatively few moving parts, that may be assembled remotely from the point of manufacture and assembled and attached to the frame without the use of specially adapted tools, and which is capable of being placed and maintained in either a retracted or extended position.